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Canadafix
Canadafix, Canadian class A certified
Category: Ford
Satisfied Customers: 1632
Experience:  Canadian automotive technician.Class "A" certified
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Ford escort: code p1506 on a 98 escort

Customer Question

code p1506 on a 98 escort
Submitted: 5 years ago.
Category: Ford
Expert:  Canadafix replied 5 years ago.
Hello and welcome back to Just Answer.

My name is Bernie and I will assist you with your question.

The code you listed is for the idle air control valve.
Are you experiencing idle difficulties? If so, is it too high or too low?

How many miles are on your Escort?

I'd appreciate all you can tell me with your problem so I can help you along.

Thank you.
Bernie.
Customer: replied 5 years ago.
188000 it runs high when you stop but only for a few sec.re placed just about everything on it new pvc,new icv,cheched for vac leaks and i still get the code
Expert:  Canadafix replied 5 years ago.
Hello.
This is not a code I see often.
If the IAC has been replaced there is possibly a wiring problem to it.

Have you checked the wiring harness from it to the PCM for shorts?
Power is applied to the IAC and the PCM grounds the circuit to open it.
If the white/light blue wire shorts to ground it opens the IAC.
It also could be a PCM grounding when it should not be.
Monitoring this circuit may be the best way to test it.

There are other possibilities. This is a section of the diagnostic chart.
Customer: replied 5 years ago.
there are no vac leaks replaced the vac rail and pvc also replaced pcm in it too replaced speed control senor and pvc hose still i get this code at the end of my wits on this car
Expert:  Canadafix replied 5 years ago.
OK
Have you checked the white/light blue wire for a short to ground?

A problem like this can be very frustrating.
It's time to rationalize the problem.

Something is making the idle run high. In order for this to take place it has to be getting air.
Where is this air coming from?
Brake booster?
A hidden vacuum leak?
Or is it the idle air control?

If you monitor the ground circuit at the idle air control to see if it is grounding out that will verify the air source.
Once verified you can continue to look there.
If it isn't then you need to look elsewhere.

You could also run with the IAC disconnected. You would have to use the throttle to keep it running.

Have you ever had it hooked up to a scanner capable of reading the data stream from the other sensors?
Perhaps there is one that is sending a wrong signal (such as a tach/RPM reading) and the PCM sends a IAC open command.
Customer: replied 5 years ago.
ok just ti let you know when i disconneck the iac the idle dose go down but the car dos'nt stall is the car running right then
Expert:  Canadafix replied 5 years ago.
Your Escort should run with it disconnected when it is warmed up. But just barely.

The throttle may be open too far if it runs higher than that.
If it is, the throttle position sensor may be sending a signal too high for idle.
Customer: replied 5 years ago.
ok i will check that in the morning and get back to you ok
Expert:  Canadafix replied 5 years ago.
That is fine.
See you tomorrow.
Bernie.
Customer: replied 5 years ago.
hi its john i was thinking dose the map sensor have any thing to do with the idle being so high because i took off the rubber boot and the idle went down
Expert:  Canadafix replied 5 years ago.
Hello John
The map sensor reads engine vacuum.
It may or may not be the problem.
Busy at my shop right now. If you can, let me think a little on this.
I'll get back to you through the noon hour.
Thank you.
Bernie
Customer: replied 5 years ago.
ok thanks
Expert:  Canadafix replied 5 years ago.
Hello John.
Your Escort does not have a Map sensor.
It does have mass air flow sensor.
It is possible that it does have a problem. Quite common.
Often the sensor wire which is very small can accumulate a layer of dust and throw off the actual air flow.
Remove the sensor carefully and clean off the wire. Be very gentle with it as it is easily damaged.
let me know if it helps.

Bernie
Customer: replied 5 years ago.
just put in a new mass air sensor but it did not help
Expert:  Canadafix replied 5 years ago.
Hello.

I should have mentioned to you not to replace it yet.
Most of the time it is an accumulation of dirt on the wire.

Have you checked the EGR valve for leaks?
If it is leaking it can create the erratic idle issue.
Begin with pulling the vacuum hose from the top of it and running.
If it improves then a solenoid is allowing vacuum to the valve at idle. It should not be.

Often the valve itself can stick open and it allows exhaust gas back into the intake at idle.
If the valve isn't too rusted up, remove it and see if you can blow through the port.
It should be sealed.If you can blow through it it should be replaced.
Customer: replied 5 years ago.
ok i will check that too also i just got a new ecm just in case the new one was bad
Expert:  Canadafix replied 5 years ago.
Hello.
The ECM is rarely a problem.
Have a look at the EGR and let me know.
Thank you.
Bernie.
Customer: replied 5 years ago.
ok i took off the hose from the egr and it ran the same threr is no vac coming from the hose at idle.pass on gas pedel and it takes 8 sec. to go down to the ilde
Expert:  Canadafix replied 5 years ago.
Pull the EGR off and check it out.
It may be leaking exhaust.
Chat later.
Bernie